2.4GHz Single Balanced Mixer Andrew Bacon Jacqueline Griffin John Stone.
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Transcript of 2.4GHz Single Balanced Mixer Andrew Bacon Jacqueline Griffin John Stone.
2.4GHz Single Balanced Mixer
Andrew Bacon
Jacqueline Griffin
John Stone
Mixer Specifications
IF Frequency: 140 MHzRF Frequency: 2400-2485 MHzRF Power: -10 dBmLO Frequency: 2260-2345 MHzLO Power: 8 dBmConversion Loss: > -9.5 dBLO-RF Rejection: < -20 dBLO-IF Rejection: <-30 dB
Mixer Design
Balun Design and Simulation
•Used an r of 2.9 for second layer to compensate for it being buried.
Diode Model and Simulation
Matching Design and Simulation
Find input impedance of diodes at 2.4 GHzDesign single stub network between
diodes and balunLet simulator optimize LC filter at output
Mixer Layout
LO Return
IF Block
LO Port
RF Port
Diode Matching Circuits
LC LPF
Coupler
IF Port
Diode
Ghetto Lettering
2.6 in
1.7 in
Resulting Board (Problems)
All holes that were supposed to be connected to ground were not
All holes that were not supposed to be connected to ground were
Missing parts of Traces
Mixer Board
Top View Bottom View
Measurement Methodology
Down Converter Used spectrum analyzer because it has low
error (~.1dB) Low frequency cable was taken out of
measurement through calibration High frequency cable was taken out of
measurement by measuring the response of the cable after measuring the mixer
Used spectrum analyser to measure IF rejection
Measurement Diagram (Down Converter)
IF RF
LO
2.260 000 00 GHz
Vector Network Analyzer
RF LO
LO Signal Generator
Downconversion Results
RF Freq
(GHz)
2.4 2.44 2.485 2.4 2.44 2.485
LO Freq
(GHz)
2.26 2.30 2.345 2.26 2.30 2.345
Conv. Loss
-10.78 -11.48 -13.00 -8.475 -8.588 -18.52
LO-IF Isolation (dBm)
-59.3 -60.5 -58.79 -71.37 -69.31 -69.99
Measurements Simulation
Downconverter MeasurementsRF Freq = 2.40 GHz RF Freq = 2.44 GHz
RF Freq = 2.485 GHz
Frequency Shift Measurements
Conversion Loss
-11.5
-11
-10.5
-10
-9.5
-9
-8.5
-8
1.73 1.83 1.93 2.03 2.13 2.23 2.33
Frequency (GHz)
Co
nve
rsio
n L
oss
Desired Frequency Response
Results
Adjusting the IF return led to being able to shift the frequencyBand up to 2.0 GHz on another board
If inductor were used this adjustment would be much easierAs stub is shorted to ground at end.
RF freq
Con
vers
ion
Lo
ss
Simulation Verification
RF freq (GHz)
Con
vers
ion
Lo
ss
Measurement Methodology
Up ConverterUsed spectrum analyzer
Measurement Diagram (Up Converter)
1 400000 00 MHz
2.260 000 00 GHz
IF RF
LO
IF Signal Generator
LO Signal Generator
Upconversion Spurious Levels
Freq Range (GHz)
Spurious
Spec
LO 2.26 GHz
LO 2.30 GHz
LO 2.345 GHz
LO 2.26 GHz
LO 2.30 GHz
LO 2.345 GHz
2.4-2.485
<-50 dBc -- -- -- -- -- --
2.485-2.90
< -40 dBc
-33.55
-43.9
-46.54 -40.43 -41.28
-36.85
-39.58
-41.91
-40.83
-43.53
2.325-2.40
< -40 dBc
-- -- -- -- -- --
1.0-2.212
<-30 dBc -36.62
-45.89
-35.92
-44.69
-35.89
-35.4
-49.77
-43.87
-44.06
-50.49
-41.35
-76.62
Measurements Simulation
Upconverter MeasurementsLO Freq = 2.26 GHz LO Freq = 2.30 GHz
LO Freq = 2.345 GHz
Upconverter Sweep Measurement• LO Frequency Swept from 2.26 GHz to 2.345 GHz
LO-RF Isolation
LO-RF Isolation
-30
-29
-28
-27
-26
-25
-24
-23
-22
2.26E+09 2.28E+09 2.30E+09 2.32E+09 2.34E+09
Frequency (Hz)
S21
dB
Simulations vs. Measurements
Possible Reasons for inaccuraciesFabrication (~.5dB)Inaccurate r
Multilayer simulation problems with ADS
Improvements
Use inductor for IF return (will allow more tuning)
Verify technology parametersVerify ADS’s simulation abilities
Questions